1. Technical Field
The present invention relates to a Voice over Internet Protocol (VoIP) terminal supporting an optimal intercom service and a session connecting method thereof.
2. Related Art
The general concept of Voice over Internet Protocol (VoIP) will be briefly discussed as follows.
VoIP can be defined as a technology which enables an existing data communication packet network to be used for Internet phones. That is, VoIP is a communication service technology for converting voice data into an Internet protocol data packet in order to support telecommunication in the data communication network as in a common telecommunication network.
As a major advantage of the VoIP Internet technology, it is possible to realize a telecommunication service using an existing IP network as it stands, thereby providing telephone users with long distance and overseas call services on Internet and intranet environments. Accordingly, the telephone users can enjoy the long distance and overseas call services while paying only local call rates.
The VoIP was provided by the VoIP forum through endeavors of major equipment companies, such as Cisco, Vocaltec, 3Com and NetSpeak, for the purpose of encouraging the use of a standard, such as ITU-T and H.323, which transmits voice, and optionally with video, using IP on the Internet or an intranet. In order to promote directory service standards, the VoIP forum also enabled users to locate other users, and to use touchphone signals for automatic telephone exchanges and voice mails.
In addition to the original IP function of the VoIP, Real Time Protocol (RTP) is used to support timely arrival of packets. If a conventional public network is used, Quality of Service (QoS) support for telecommunication is difficult due to best-off service characteristics. Accordingly, it is possible to provide higher quality VoIP services by using a private network which is managed by a separate company or an Internet Telephony Service Provider (ITSP).
In the case of the conventional Plain Old Telephone Service (POTS) (e.g., PSTN), a plurality of telephones can be used in a single home based upon a bridge function. An intercom service has also been provided to users using the same. Recently, as POTS phones used at home have been replaced with VoIP phones with the arrival of VoIP markets, consumers have requested conventional POTS phone functions together with additional VoIP phone functions. However, the intercom function has not been enabled on such a VoIP phone.